Interference Assisted Lithography IAL A Way to Contain

Interference Assisted Lithography (IAL): A Way to Contain the Lithography Costs for the 32 nm and 22 nm Half-Pitch Device Generations Rudi Hendel; David Markle; John S. Petersen; Andrew Barada; Periodic Structures, Inc. Zhilong Rao Applied Materials, Inc.

Presentation Overview Semiconductor Manufacturing Costs: A quick calibration Cost Model Overview Basics and Assumptions Interference Assisted Lithography An introduction into the Concept Process and Lithography-related cost factors and their impact Results and Discussion Conclusions October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 2

“Lithography is a Bargain!*” * Paul Arnold, ASML at the VLSI Litho Panel 2008 (November 18, 2008) 450 mm projections Pixel Transfer Rate October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 3

Still – Time for Reality Check: (Comparing the price-tag for a Fab with…. ) Megafab: $6 B to $10 B $5 B $3 B $1 B October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 4

Should the size of Fab Price Tags be a concern? Yes Bob Johnson (Gartner DQ) at ISS 2009 October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 5

The basis of our Cost Model: Tool component – Depreciation and Tool Maintenance Allocation of Mask Cost Process Cost (Resist, Develop, BARC, Metrology, Inspection, etc. Model by “Screenivasan et al. ” as quoted by Frank Goodwin, November 7, 2005 – Trends in the Cost of Photolithography October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 6

Cost of Lithography Direct Impact Costs Cost and Complexity of the Patterning Process Cost of additional Tools required (ex. : S. I. T. ) Cost of Mask(s) Depreciation Cost and Maintenance Expense of the Exposure Tool Indirect Impact Costs (Factors of high importance to a customer on which the Choice of Lithography has a critical impact) Cost of Design Time to Design Implementation Risk of First Silicon Fail Tool Price to Customer Effective Throughput Scheduled & unscheduled Maintenance October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 7

Per Yan Borodovsky; Semicon West; July 15, 2009 October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 8

How to reduce cost? Start with the Tool Either: Simplify the pattern, reducing Pixel Transfer Rate which leads to lower capital cost Or: Trade off general purpose capability with acceptable restrictions leading to cost savings Pixel Transfer Rate October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 9

Effective Means to segment (and reduce) Information Content contained in a pattern: Interference Assisted Lithography n It separates high frequency component of the image (dense line-spaces) from the design content (line-ends) Simplified Imaging Rules allow lower tool cost n without sacrificing minimum resolution Several technology approaches are available n Ultimate Selection will accommodate key requirements in both, logic and memory. October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 10

What is Interference Assisted Lithography? I. A. L. is a two-exposure process: n n Exposure One – Fixed Pitch Pattern (a grating) Exposure Two – a Block-Mask, determining where the lines defined in the first exposure end and start + October 23. 2009 = Periodic Structures, Inc. Lithography Extensions Conference, Prague 11

The I. A. L. Technology Principle has been demonstrated Source: MIT Lincoln Lab (2005) M. Fritze, T. M. Bloomstein, B. Tyrrell, T. H. Fedynyshyn, N. N. Efremow, D. E. Hardy, S. Cann, D. Lennon, S. Spector and M. Rothschild, “Hybrid Optical Maskless Lithography: Scaling Beyond the 45 nm Node”, J. Vac, Sci. and Tech. B 23(6) (2005), pp. 2743– 2748. October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 12

Benefits of Interference-based Exposure Tools Cost benefits n n n Simplified Optics and thus lower Tool Cost OL requirements for IAL are relaxed compared to OL requirements for traditional Double Patterning Significant savings in Cost of Masks IAL requires 1 critical mask, Double Patterning requires 2 + Technical Benefits n n Wider process window Increased Contrast/DOF October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 13

Double Patterning: – Comparing Traditional D. P. vs. I. A. L. D. P. The reduced Cost of Masks gives IAL DP a 30% cost benefit compared to Traditional DP (Independent of Mask Usage) October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 14

Total Litho Cost by Node: Assignment of Mask Levels October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 15

Total projected Lithography Cost of Lithography per Wafer Traditional D. P. vs. I. A. L. D. P. Traditional Double Patterning I. A. L. Double Patterning October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 16

Total projected Lithography Cost of Lithography for the Node Hypothetical Case of replacing all EUV Layers with IAL Traditional Double Patterning I. A. L. Double Patterning Only I. A. L. DP for Critical Layers October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 17

Additional Benefits Possible with I. A. L. (System Architecture Dependent) Reduced Capital Cost benefits all Lot Sizes In the case of a reduced Exposure Field (Not all applications require large Exposure Fields) n Further Mask Cost Reduction Minimizing write/inspection costs Particularly benefitting small lot sizes, which are highly sensitive to Mask Cost n n Reduced Systems Cost (Stepper architecture allows systems simplifications) Additional efficiency particularly for small devices (somewhat counterintuitive) October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 18

Mask Cost vs. Mask Patterned Area October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 19

Cost of Lithography Comparison – Traditional Scanner vs. I. A. L. Stepper October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 20

I. A. L. Limitations High Regularity requires Design Restrictions n I. A. L. Restrictions are similar to Sidewall Image Transfer (S. I. T. ) Restrictions Yet, S. I. T. is considered as one viable option for extending resolution. Designs compatible with S. I. T. are expected to be compatible with I. A. L. . n Adopting such restrictions early and transitioning to regularity in one single step promises significant cost benefits. October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 21

In Summary – Cost Benefits of I. A. L. : Direct: Significant reduction of Mask Cost n Comparable layers (vs. traditional DP) Containment of Litho Cost Increases n If applied to all Critical Levels in the process flow Additional Benefits are possible: n n Reduced Die Size, Small Lot-size, (leading to smaller Exposure Fields) Enhanced Maskless Lithography Economics Reduced Image (Pixel) Density for Block Mask Enables competitive MLL Throughput (prototyping) October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 22

In Summary – Cost Benefits of I. A. L. : Indirect: I. A. L. can become a Technology Enabler for a market segment currently underserved: n Opening Access to Leading Edge Geometries for low/medium mask usage applications (ASIC/ASSP) by: Reduced Mask Costs (and Capital Cost) Simplified DR complexity Reduced time to Design Completion Reduced risk to first time success October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 23

Acknowledgements Al Bergendahl, Bergendahl Enterprises Marc Levenson Mark Pinto, Applied Materials Hans Stork, Applied Materials Bill Tobey, ACT Consulting October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 24

Thank you! October 23. 2009 Periodic Structures, Inc. Lithography Extensions Conference, Prague 25